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View Full Version : Can macroblock alignment optimize direct MPEG-2/4 re-encoding?


unplugged
25th June 2002, 15:06
Even with high bitrate MPEG-2 movies the macroblock "chessboard" is pretty visible when zooming 2X or 4X, so standard macroblock seems to be 8x8 :p.
Since this blocks creates color-level steps especially "visible" for the encoder (when don't apply any resize or filter), does give benefits to choose the crop area aligned by 8 pixels? :D

Can this optimize the encoder efficiency? (MPEG-4)
(having new macroblocks NOT ACROSS past macroblocks)

Example:
MPEG-2 movie 720x576, crop image size 704x432
image border exact crop point at (4,70)
macroblock aligned crop point at (8,72)

Acaila
25th June 2002, 15:20
Did you read this (http://forum.doom9.org/showthread.php?s=&threadid=18277&highlight=crop+mod) thread? It deals with that very subject.